local PLUMBING'S BLOG POST
Conor Crawford • April 12, 2025
Do All Homes Really Need a Water Heater Expansion Tank?
At Local Plumbing, we often get asked whether a water heater expansion tank is necessary. While not every home requires one, for many properties in San Rafael, Mill Valley, Petaluma, and across Marin and Sonoma Counties, this small device can prevent big plumbing problems.
So, what exactly is a water heater expansion tank—and how do you know if your home needs one? Let’s break it down.
What Is a Water Heater Expansion Tank?
A water heater expansion tank, also known as a thermal expansion tank, is a small pressurized tank installed near your water heater. Its job is to absorb excess water pressure created when water heats up and expands. Without an expansion tank, this added volume has nowhere to go, and that pressure can damage your plumbing system—leading to:
- Leaks
- Burst pipes
- Damaged valves
- Water heater failure
Why Are Expansion Tanks Important?
Your plumbing system is designed to operate within a safe pressure range. When that pressure spikes repeatedly—especially in closed-loop systems with check valves or pressure regulators—it can wear out your pipes, fittings, and appliances.
An expansion tank acts as a shock absorber. It protects your water heater, pipes, and pressure relief valve by reducing stress on the system and limiting unnecessary water discharge from the relief valve.
Do Homes in Marin or Sonoma County Need Expansion Tanks?
Not every home needs one, but many homes in Marin County and Sonoma County do—especially if:
- Your home has a pressure-reducing valve (PRV) or backflow preventer
- You have high static water pressure (above 80 PSI)
- You recently replaced your water heater (code enforcement often requires expansion tanks for new installs)
- Your plumbing system is closed-loop
In California, the California Plumbing Code (CPC) mandates the use of expansion tanks in homes with closed systems. Most homes with PRVs or backflow devices fall into this category, meaning excess pressure has no route back into the municipal water supply.
Signs You Might Need an Expansion Tank
If you’re not sure whether your home needs one, here are some red flags that could indicate pressure-related issues:
- Dripping from the water heater’s pressure relief valve
- Sudden fluctuations in water pressure
- Leaks around pipe joints or fittings
- Water hammer (banging noises in your pipes)
- Shortened lifespan of plumbing components
When Is an Expansion Tank Not Needed?
Some homes can safely operate without a water heater expansion tank. Here’s when it might not be necessary:
- Tankless Water Heaters: These don’t store hot water, so thermal expansion doesn’t occur.
- Open-Loop Systems: In these setups, extra pressure can escape back into the city water line.
- No PRV or Backflow Preventer: If your home is older and doesn’t have a closed-loop system, an expansion tank may not be required (but we still recommend a pressure evaluation).
Expansion Tank vs. Pressure-Reducing Valve (PRV)
Homeowners sometimes confuse the two, but they serve different functions:
- A PRV controls the overall incoming water pressure.
- An expansion tank handles the increased pressure caused by heating water.
Many homes need both to properly manage pressure and protect plumbing components.
Choosing the Right Expansion Tank Size
The correct expansion tank size depends on your water heater’s capacity and your home’s water pressure. Here are a few things to consider:
- Water Heater Size (gallons)
- Static Water Pressure (measured in PSI—if it’s over 80, action is needed)
You can use an online expansion tank sizing calculator or call Local Plumbing for a quick evaluation. We’ll help you determine the right size and model to fit your system.
Need Help? Call Local Plumbing
If you're unsure whether your San Rafael or Petaluma home needs an expansion tank—or you're experiencing plumbing issues that could be related to pressure—give us a call.
At Local Plumbing, we provide expert water heater services, code-compliant installations, and professional plumbing inspections throughout Marin and Sonoma Counties. We’ll help you stay up to code, avoid costly damage, and get the most out of your plumbing system.
Call us today to schedule a consultation!
Serving San Rafael, Mill Valley, Novato, Petaluma, and surrounding areas
I am happy to annouce Local Plumbing will be taking part in the Cool Petaluma Future Fest 2025 on Sunday, May 4th, at the Petaluma Community Center at Lucchesi Park! The Future Fest is all about promoting climate action, and we’re proud to be part of the movement, particularly in our home town. On the day we’ll be showcasing the latest in energy-efficient home technology — specifically, we have a nice feature on Heat Pump Water Heaters, with a physical demo Heat Pump there to see. Heat pump water heaters are one of the smartest upgrades homeowners can make today. They use up to 70% less energy than traditional gas water heaters, helping to significantly reduce your home’s carbon footprint. Learn how heat pump water heaters work See a real unit up close Talk to our expert plumbers about installation, rebates, and how switching can make a big difference for your home and the environment We’re passionate about helping Petaluma move toward a more sustainable future — and we’d love for you to stop by, say hello, and discover how easy it is to upgrade your home's water heating system. Event Details: 📍 Petaluma Community Center at Lucchesi Park 📅 Sunday, May 4, 2025 ⏰ 12:00 PM – 4:00 PM Come check out our display, meet our team, and enter for a chance to win fun prizes! Let’s build a cooler, greener Petaluma — together.
Powering Comfort: Local Plumbing & Rocky Hill Electric's Seamless Collaboration on Heat Pump Installations in San Rafael
This week we just moved into to our new office and warehouse location in San Rafael, which is a more central location for us to work out of as part of serving the Marin area. We just got the keys this week and over the next few weeks we will continue to build out the area to make our work flow more efficient. With plans for a plumbing technical training area along with a live fire water heater testing section, to ensure our plumbing and boiler technicians are the best trained in the Marin area. With Local Plumbing's move to San Rafael we ensure an even more efficient plumbing service response time for all our clients. We will continue to update you all on our progress here as well as our social channels.
Discover the benefits of radiant heating boiler system installation in Corte Madera, CA. Contact Local Plumbing for professional installation and service.
Backflow prevention devices are an essential part of protecting your home’s drinking water from contamination. If you’re a homeowner in Marin County, you may be required to install a backflow prevention device on your water service—whether it’s for your domestic water supply, fire sprinkler system, or irrigation. But when is it necessary, and what are the requirements for Marin Water customers? At Local Plumbing, we specialize in backflow prevention installations, testing, and repairs. Here’s what you need to know about keeping your water safe and in compliance with local regulations. What Is a Backflow Prevention Device? A backflow prevention device is a specialized valve designed to stop water from flowing backward into the public water supply. Backflow can occur when there’s a sudden drop in water pressure—like during a firefighting event or a major pipe break—causing contaminated water from private plumbing systems to siphon back into the municipal supply. Common contaminants include: Fertilizers and pesticides from irrigation systems Household cleaning chemicals Bacteria and debris from stagnant or non-potable water sources To prevent this, Marin Water requires certain properties to have backflow prevention assemblies installed and tested annually. When Do You Need a Backflow Prevention Device? Marin Water’s regulations specify that backflow prevention is required in situations where there is a potential risk of contamination. You may be required to install one if: 1. You Have a Fire Sprinkler System Fire sprinkler systems are often connected to the municipal water supply but contain standing water, which can stagnate over time. If backflow occurs, this water could re-enter the drinking supply. To prevent this, Marin Water requires all homes with fire sprinkler systems to have an approved backflow prevention assembly. 2. You Have an Irrigation System Irrigation systems can introduce contaminants like fertilizers, pesticides, and bacteria into your home’s plumbing. If your property has an irrigation system connected to Marin Water’s supply, a backflow prevention device is likely required. 3. Your Home Has an Alternate Water Source If you use a well, rainwater harvesting system, or any other alternative water supply, you are required to install a backflow prevention device to prevent cross-contamination between these sources and the public water system. 4. You Own a Multi-Unit Property or Commercial Building Certain commercial and multi-residential buildings are required to have backflow prevention in place to ensure the safety of all occupants and the broader community. How to Stay in Compliance with Marin Water’s Backflow Regulations Marin Water requires: Initial installation: If you are adding a fire sprinkler, irrigation system, or another potential backflow hazard, a backflow device must be installed by a licensed professional. Annual testing: Once installed, backflow devices must be tested annually by a certified backflow tester to ensure they are functioning properly. Repairs and replacements: If your backflow prevention device fails a test, repairs or replacement may be required to remain compliant. Why Backflow Prevention Matters for Your Home Besides meeting local regulations, installing a backflow prevention device helps: ✅ Protect your drinking water from potential contaminants ✅ Prevent costly plumbing issues caused by backflow contamination ✅ Ensure your home is in compliance with Marin Water’s requirements ✅ Avoid fines or water service interruptions due to non-compliance Need a Backflow Prevention Device Installed or Tested? We Can Help! At Local Plumbing, we specialize in installing, testing, and repairing backflow prevention devices for Marin homeowners. If you’re unsure whether your home requires one or need annual testing, give us a call!
If you’re a homeowner in Lucas Valley-Marinwood, CA, you know that plumbing problems can arise at the worst possible times. Whether it’s an aging water heater, a clogged drain, or a sudden leak, having a reliable local plumber is crucial. At Local Plumbing, we specialize in residential plumbing services in Marin County, ensuring that your home's plumbing system runs smoothly year-round. Top Plumbing Issues in Lucas Valley-Marinwood, CA 1. Aging Pipes and Leaky Fixtures Many homes in Lucas Valley-Marinwood were built decades ago, meaning they often have aging plumbing systems. Over time, pipes corrode, joints loosen, and leaks develop, leading to water damage, high water bills, and reduced water pressure. If you’ve noticed a spike in your water bill or damp spots on walls or ceilings, it may be time to schedule a plumbing inspection with our experts at Local Plumbing. 2. Sewer Line Blockages & Tree Root Intrusion One of the most common plumbing emergencies we handle in Marinwood and Lucas Valley is sewer line backups caused by tree roots and ground shifting. These blockages can result in slow drains, foul odors, or sewage backups in your home. Our team at Local Plumbing provides trenchless sewer repair and hydro-jetting services to remove blockages and restore flow—without tearing up your yard. If you’re experiencing slow or gurgling drains, don’t wait! Call us today for a video sewer line inspection. 3. Water Heater Repair & Installation Is your water heater struggling to keep up? Whether you have a traditional tank-style heater or a tankless system, regular maintenance is key to preventing costly breakdowns. Hard water in Marin County can cause sediment buildup, which reduces efficiency and shortens the lifespan of your unit. At Local Plumbing, we offer: Water heater flushes & maintenance New tank & tankless water heater installation Water heater repairs for all major brands If your hot water is running out too quickly or your system is over 10 years old, call us for a free estimate on a new energy-efficient water heater today! 4. Drain Cleaning & Hydro-Jetting Slow drains? Recurring clogs? If DIY methods aren’t cutting it, you may need professional drain cleaning services. Our team at Local Plumbing specializes in: Hydro-jetting – High-pressure water clears out grease, debris, and tree roots Snaking & drain augering – Removes stubborn blockages without damaging pipes Preventive drain maintenance – Keep your pipes flowing smoothly year-round If you’re experiencing frequent drain backups in Lucas Valley-Marinwood, contact us today for a same-day drain cleaning service. 5. Emergency Plumbing Services – 24/7 Support Plumbing emergencies don’t wait for business hours, and neither do we! At Local Plumbing, we offer 24/7 emergency plumbing services in Lucas Valley-Marinwood, so you’re never left dealing with a crisis alone. Common emergency calls we handle include: Burst pipes & major leaks Sewer line backups No hot water issues Gas leaks & emergency gas line repairs If you need fast, reliable emergency plumbing in Marin County, give us a call anytime—we’re here to help! Why Choose Local Plumbing? Licensed & insured local plumbers Fast response times & same-day service Fair, upfront pricing with no hidden fees Trusted by homeowners in Lucas Valley-Marinwood for years Schedule Your Plumbing Service Today! Whether you need drain cleaning, a water heater upgrade, sewer line repair, or emergency plumbing in Lucas Valley-Marinwood, CA, Local Plumbing has you covered. Call us today at 415-484-0454 or schedule your service online for fast, friendly plumbing you can trust.
Emergency plumbing service and repairs for Tiburon CA by Local Plumbing
Family Fun Events in Marin County: Exciting Activities for the Whole Family
If your home or business has plumbing fixtures below the main sewer line, you need a sewage ejector pump or sump pump to keep things flowing smoothly. These essential systems prevent flooding, water damage, and costly repairs by efficiently managing wastewater and groundwater. At Local Plumbing, we specialize in sewage ejector pump installation, sump pump replacement, and emergency pump repairs. Read on to learn why these pumps are critical for your plumbing system and how our expert team can help. What Is a Sewage Ejector Pump? A sewage ejector pump is designed to move wastewater from lower levels, such as basements or below-grade bathrooms, up to the main sewer line. These pumps are essential for homes with basement bathrooms, laundry rooms, or utility sinks that sit below the gravity-fed sewage system. Without a properly functioning sewage ejector pump, waste and water can back up, leading to messy and expensive problems. Signs You Need a Sewage Ejector Pump Replacement: Frequent clogging or backups in basement plumbing Unusual noises or vibrations from the pump Sewage odors near the pump area Pump fails to turn on or off properly Standing water in the pit If you experience any of these issues, it may be time to replace your sewage ejector pump. Our licensed plumbers at Local Plumbing can assess the condition of your pump and recommend the best solution for your home or business. What Is a Sump Pump? A sump pump protects your basement or crawl space from flooding by removing excess groundwater. It sits in a sump pit and automatically activates when water levels rise, pumping water away from your foundation to prevent moisture damage and mold growth. Do You Need a Sump Pump? Do you have a basement or crawl space prone to flooding? Have you noticed dampness, mold, or musty odors in your lower levels? Has your current sump pump failed or aged beyond its lifespan (typically 7-10 years)? If you answered yes to any of these questions, a new sump pump installation or replacement could save you from costly water damage. Choosing the Right Pump for Your Home At Local Plumbing, we help homeowners and businesses choose the right sewage ejector or sump pump based on their specific needs. We install and service top brands like Zoeller, Liberty, and Wayne to ensure reliable, long-lasting performance. Our team also offers battery backup sump pump installations to keep your home protected even during power outages. Expert Pump Installation and Repair When it comes to sewage ejectors and sump pumps, proper installation is crucial to avoid failures and inefficiencies. Our skilled technicians handle everything from pump sizing to professional installation, ensuring your system runs smoothly for years to come. We also provide 24/7 emergency plumbing services for unexpected pump failures. Why Choose Local Plumbing? Licensed and insured plumbers with years of experience Fast, reliable service for repairs and replacements Top-rated customer reviews and satisfaction guarantees Affordable pricing and upfront estimates Schedule Your Pump Service Today Whether you need a new sump pump installation, a sewage ejector pump replacement, or emergency repairs, Local Plumbing has you covered. Contact us today for a free consultation and estimate. Protect your home from backups and flooding with expert plumbing solutions!
Welcome to Local Plumbing, the trusted name for top-quality plumbing services in Kentfield, California. Whether you’re dealing with a minor leak or planning a major installation, our skilled team is here to provide exceptional service and ensure your home’s plumbing system runs smoothly. Discover the range of services we offer and why homeowners in Kentfield choose us as their go-to plumbing experts. Our Comprehensive Plumbing Services in Kentfield 1. Emergency Plumbing Repairs Plumbing emergencies can happen at any time, and when they do, you need a reliable team that can respond quickly. From burst pipes to severe clogs, we provide 24/7 emergency plumbing services to keep your home safe and functional. 2. Drain Cleaning and Hydro Jetting Clogged drains can disrupt your daily routine and cause significant damage if left unchecked. Our advanced drain cleaning services, including hydro jetting, effectively remove stubborn blockages and restore proper flow to your plumbing system. 3. Water Heater Installation and Repair Enjoy reliable hot water year-round with our expert water heater services. We specialize in traditional tank and tankless water heater installation, repair, and maintenance. We proudly install top brands like Navien and Rheem to ensure long-lasting performance. 4. Leak Detection and Repair Leaks can lead to higher water bills and property damage if not addressed promptly. Using state-of-the-art technology, we pinpoint and repair leaks efficiently, whether they’re in your pipes, water main, or slab foundation. 5. Sewer Line Repair and Replacement Sewer line issues can cause unpleasant odors and backups in your home. Our team handles everything from minor sewer line repairs to full replacements, ensuring your system functions flawlessly. 6. Fixture Installation and Upgrades Upgrading your fixtures can enhance your bathroom or kitchen’s appearance and efficiency. From TOTO Washlet seats to modern faucets, we offer expert installation for all types of fixtures to meet your style and functionality needs. 7. Repiping Services Older homes in Kentfield often have outdated plumbing systems that are prone to leaks and inefficiency. We provide whole-home repiping services using durable materials like PEX or copper to ensure a reliable and efficient system. 8. Water Filtration Systems Improve the quality of your drinking water with our advanced water filtration system installations. Our solutions remove impurities, providing your family with clean and safe water straight from the tap. Why Choose Local Plumbing for Your Kentfield Home? Experienced Professionals: Our team of licensed plumbers brings years of experience and expertise to every job. Fast Response Times: We understand the urgency of plumbing issues and strive to provide prompt service. Transparent Pricing: No hidden fees—just upfront, honest pricing for all our services. Customer Satisfaction: We prioritize your satisfaction and go above and beyond to exceed your expectations. Eco-Friendly Solutions: From water-saving fixtures to energy-efficient water heaters, we’re committed to helping Kentfield homeowners reduce their environmental footprint. Schedule Your Plumbing Service Today When you need reliable plumbing services in Kentfield, California, turn to the experts at Local Plumbing. Whether it’s a routine maintenance check or an urgent repair, our team is ready to help. Call us today or schedule your appointment online to experience the Local Plumbing difference.
